This SBIR Phase I project will develop a software package that provides methodologically sound attentional tests for the evaluation of treatments for attention deficits. This software product, the Praxis Attentional Inventory (PM), is primarily targeted to objectively assess stimulant medication response in ADHD children. We have applied a rigorous set of criteria to identify clinically-relevant behavioral paradigms that meet scientific scrutiny. Further, we have limited our choice of tests to ones that have been rendered biologically intepretable by neuropsychology and brain imaging studies. The initial product will assess frontal lobe function, which is thought to be markedly impaired in ADHD. The end-product provides user-friendly protocols for clinical use, along with design flexibility that meets experimental analytic standards. We plan to implement working prototypes of all user-interface modules and tests on the Macintosh computer platform, and to conduct two-stage field tests to verify the product's usability and effectiveness. Should Phase I prove successful, we plan a Phase II application to produce a full implementation for both Macintosh and PC/Windows platforms, with integrated access to the Praxis Internet web site for on-line user support, libraries of preconfigured tasks, data management, and statistical support services. PROPOSED COMMERCIAL APPLICATION: The product being developed and evaluated is relevant to a potentially enormous population of ADHD children who are administered medication trials. Children diagnosed as ADHD and prescribed stimulant drugs have been estimated to number in the millions in the US (see Significance). This inventory will also find application in the study of adults with ADHD (residual type), and non-ADHD individuals with deficient attention (e.g., autistic disorder), for whom therapeutic interventions must also be evaluated.